Analysis On Subsidence Of The Four-Wheels-Three-Axes Mobile Subsystem’s Wheel And Study On Escape Strategy Of The Subsystem

The lunar rover is the key equipment of lunar exploration project, which is critical for successful completion of probing reconnaissance mission. The trafficability, mobility, lunar environment adaptability and escaping control strategies of the lunar rover in limit conditions are important conditions for the lunar rover to carry out the exploration missions smoothly. At present, due to differences of geological conditions, geographical location, soil depth, and soil maturity, as well as the incomprehensibility of lunar surface environment, the differences of the lunar soil always exist objectively. At the same time, because of the gravity effects, environmental factors, the differences of measurement methods, instrument errors and other reasons, they will also cause differences between the properties of lunar soil measured on the ground and the real properties of lunar soil parameter value. So making up or eliminating these differences, studying the mobility of the lunar surface mobile subsystem and researching the escape strategy under subsidence fault conditions are the urgent tasks we are facing.Based on the above problems, firstly, through extensive literature review, this paper analyzes, inducts and summarizes the research status and progress of planetary vehicle mobile system, the true and simulated lunar soil, lunar wheel, wheel contact model of subsidence, numerical analysis methods; secondly, based on the vehicle terramechanics theory, wheel soil contact model and lunar soil constitutive model, it establishes a sand wheel subsidence calculation finite element model, analyzes the effects of the sand wheel’s diameter and width, speed, load, slip rate of single to wheel’s subsidence, which validates the effectiveness of this theory and computational models through experiment:thirdly, based on the above theory and car body rigid body dynamics, it establishes a subsidence model of four-wheels-three-axes mobile subsystem, and simulates four-wheels-three-axes mobile subsystem under several typical working conditions through simulation calculation, analyzes the subsidence, the pothook tractive force, adhesion, driving resistance of four-wheels-three-axes mobile subsystem’s wheel; finally, based on the vehicle mobile fault theory, it establishes four-wheels-three-axes mobile subsystems fault types and calculates the most inferior limit conditions, it puts forward the escape strategy of four-wheels-three-axes mobile subsystem under some mobile fault mode.The above research results provide guidance for the structural design, optimization of lunar rover and rover subsidence escape control strategy.